Oil-water separation system for sewage discharge of external floating roof oil tank

Abstract

The invention relates to an oil-water separation system for sewage discharge of an external floating roof oil tank in the technical field of petrochemical discharge treatment. The oil-water separation system comprises an oil storage tank, a cyclone separator and a gravity separation tank, the gravity separation tank is divided into a floating separation tank and an overflow tank, the walls of the floating separation tank and the overflow tank are respectively provided with a first oil discharge pipe and a first water discharge pipe, and the floating separation tank is provided with a first liquid level meter; a lower port of the cyclone separator is connected with a discharge pipe extending into the floating separation tank, an upper port of the cyclone separator is provided with an overflow notch, an oil collecting ring groove is fixed on the outer wall of the upper part of the cyclone separator, the cyclone separator is provided with a second liquid level meter, and the oil collecting ring groove is connected with the sewage treatment plant together with the first oil discharge pipe through a second oil discharge pipe; the oil storage tank comprises an outer floating top cover and a flow blocking ring and is used for arranging a rain collecting groove and a mixing ring groove, the mixing ring groove is communicated with the side cutting inlet pipe through a first hose, and the rain collecting groove is connected with a first branch pipe, a second branch pipe and a third branch pipe through a second hose; the oil-water separation system can improve the treatment flow and the separation effect at lower cost.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical emission treatment, in particular to an external floating roof oil tank sewage oil-water separation system. Background Art

[0002] The storage tanks of large oil depots are usually set up with external floating roof structures. During the process of receiving and delivering oil in the storage tanks, the oil will adhere to the tank wall, which can be called "hanging on the wall". As the floating roof drops, the tank wall is exposed. When it rains, the hanging oil is washed down by rainwater and flows into the initial rainwater collection device. At present, the initial rainwater collection device set up in large oil depots cannot achieve automatic separation of rainwater and sewage in structure. It depends entirely on the operator's work experience to judge the rainfall size and rainfall time, and then manually switch. This setting is greatly affected by personal factors and is not very operable. During heavy rains, clean rainwater is often mixed into the sewage system, impacting the downstream sewage treatment plant, and the rainwater contains excessive oil and cannot be discharged directly; Although the existing oil-water separation technology is relatively mature, what is needed now is low-cost initial treatment upstream, and it cannot replace the complex treatment of downstream sewage treatment plants. Therefore, sedimentation tanks or gravity tanks that rely on density difference stratification have become the first choice. Not only can they perform initial separation of oil and water, but the cost is also very low. However, the defect is also very obvious, that is, the separation effect is poor, especially in heavy rain seasons with heavy rainfall. Rainwater mixed with crude oil has no time to stratify. If the volume of the gravity tank is expanded, it will occupy scarce land area, which is not worth the loss. Summary of the invention

[0003] In order to overcome the deficiencies in the background technology and solve the existing technical problems, the present invention discloses an external floating roof oil tank sewage oil-water separation system, which can improve the processing flow and separation effect at a relatively low cost.

[0004] To achieve the above object, the present invention adopts the following technical solution: An external floating roof oil tank sewage discharge oil-water separation system comprises an oil storage tank, a cyclone separator, a gravity separation tank and a downstream sewage treatment plant for collecting and treating oil pollution; the gravity separation tank is divided into a floating tank and an overflow tank by a partition wall, an overflow gate is provided at the lower part of the partition wall, the floating tank and the overflow tank are respectively provided with a first oil discharge pipe and a first water discharge pipe at the upper end of the tank wall away from the overflow gate, and a first liquid level gauge is installed on the tank wall of the floating tank between the first oil discharge pipe and the overflow gate; the lower port of the cyclone separator is connected to a discharge pipe whose end extends into the floating tank, the upper port of the cyclone separator is provided with an overflow notch on the side wall away from the side cut-in pipe, and an oil collecting ring groove is fixedly provided around the upper outer wall of the cyclone separator, and the oil collecting ring groove is connected to the upper outer wall of the cyclone separator. A second liquid level gauge is installed on the wall of the cyclone separator between the side-cut inlet pipes, and the bottom of the oil collecting ring groove is connected to the sewage treatment plant together with the first oil drain pipe through a second oil drain pipe; the oil storage tank includes an external floating roof cover that can float up and down along the tank wall, and a baffle ring is coaxially fixed on the upper cover surface of the external floating roof cover to divide the baffle ring into a rain collecting groove and a mixing ring groove inside and outside, and the bottom of the mixing ring groove is connected to the side-cut inlet pipe through a first hose, and the bottom of the rain collecting groove is connected to a first branch pipe whose end corresponds to the upper port of the cyclone separator, a second branch pipe whose end corresponds to the notch of the floating separation groove, and a third branch pipe for emptying the end through a second hose, and the first branch pipe, the second branch pipe, the third branch pipe, the first hose and the discharge pipe are all equipped with control valves.

[0005] Furthermore, an intake ring pipe is provided at the center of the bottom of the floating tank, and a plurality of upward intake branches are evenly arranged on the tube body of the intake ring pipe. The intake ring pipe is connected to an intake main pipe, and a one-way valve for one-way intake conduction is installed on the intake main pipe. The outer end of the intake main pipe is sealed and passes through the floating tank and is connected to an intake pump.

[0006] Furthermore, a slow-flow water wheel is provided in the discharge pipe, and the air intake pump is configured as a hand-cranked air intake pump. The axle of the slow-flow water wheel rotates through the wall of the discharge pipe and is correspondingly connected to the rocking shaft of the air intake pump.

[0007] Furthermore, the oil storage tank, cyclone separator and gravity separation tank are arranged in sequence from high to bottom, and a water pump is installed on the first hose.

[0008] Furthermore, an oil drain valve and an oil pump are installed on both the first oil drain pipe and the second oil drain pipe.

[0009] Furthermore, the bottoms of the flotation tank and the overflow tank are both provided with sewage pipes with sewage valves.

[0010] Due to the adoption of the above-mentioned technical solution, the present invention has the following beneficial effects: The external floating roof oil tank sewage discharge oil-water separation system disclosed by the present invention can collect most of the clean rainwater that does not contact the tank wall in the middle and a small part of the mixed oil and water that contact the tank wall separately by adding a baffle ring to the external floating roof cover, thereby reducing the processing volume; by adding a cyclone separator, the centrifugal effect is first used to perform a preliminary separation of oil and water, and the separation effect is improved while reducing the flow rate, so that the oil and water entering the gravity separation tank can be effectively separated for a second time in a limited space, and the entire separation process is carried out continuously, so that the processing requirements can be met even when the rainfall is large. More importantly, the entire system has a simple structure, does not require too much manual operation, and can be controlled at a relatively low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the implementation structure of the present invention; Figure 2 Schematic diagram of the top view of the cyclone separator.

[0012] In the figure: 1, oil storage tank; 101, external floating roof; 102, baffle ring; 2, cyclone separator; 201, side cut inlet pipe; 202, oil collecting ring groove; 203, overflow notch; 204, second liquid level gauge; 3, gravity separation tank; 301, floating separation tank; 302, overflow tank; 303, overflow gate; 304, first liquid level gauge; 4, sewage treatment plant; 5, first hose; 6, second hose; 7, first branch pipe; 8, second branch pipe; 9, third branch pipe; 10, second oil discharge pipe; 11, first liquid level gauge; 12, slow flow water wheel; 13, intake pump; 14, intake main pipe; 15, first oil discharge pipe; 16, intake ring pipe; 17, first drain pipe. DETAILED DESCRIPTION

[0013] The technical solution of the present invention will be described below in conjunction with the drawings in the embodiments of the present invention. In the description, it should be understood that if there are terms such as "upper", "lower", "front", "back", "left", "right" and the like indicating directions or positional relationships, they are only corresponding to the drawings of the present invention, for the convenience of describing the present invention, and do not indicate or imply that the devices or components referred to must have a specific direction: Embodiment 1:

[0014] Combined with Figure 1 and 2 The external floating roof oil tank sewage oil-water separation system comprises an oil storage tank 1, a cyclone separator 2, a gravity separation tank 3 and a downstream sewage treatment plant 4 for collecting and treating oil pollution. The oil storage tank 1, the cyclone separator 2 and the gravity separation tank 3 can be arranged from high to low in sequence to facilitate the natural flow of rainwater. The gravity separation tank 3 is divided into a floating tank 301 and an overflow tank 302 by a partition wall. The volume and length of the floating tank 301 are larger than those of the overflow tank 302, ensuring that the oil and water stay in the floating tank 301 for a longer time, which is conducive to stratification. As needed, the bottoms of the floating tank 301 and the overflow tank 302 are both provided with sewage pipes with sewage valves, which are convenient for cleaning and sewage after long-term use. The lower part of the partition wall is provided with an overflow gate 303, and after the floating tank 301 is stratified, the rainwater at the lower part can be discharged through the overflow gate 303. The oil passes through the overflow gate 303 and enters the overflow tank 302, while the upper oil layer is blocked by the isolation wall. The floating tank 301 and the overflow tank 302 are respectively provided with a first oil discharge pipe 15 and a first water discharge pipe 17 at the upper end of the tank wall away from the overflow gate 303. A first liquid level gauge 304 is installed on the tank wall of the floating tank 301 between the first oil discharge pipe 15 and the overflow gate 303. The first liquid level gauge 304 is generally slightly higher than the overflow gate 303, so as to facilitate the control of the water discharge to be higher than the overflow gate 303 in advance. The lower port of the cyclone separator 2 is connected with a discharge pipe 11 whose end extends into the floating tank 301, and the end of the discharge pipe 11 should also be away from the overflow gate 303. The upper port of the cyclone separator 2 is away from the side wall of the side-cut inlet pipe 201 and is provided with an overflow notch 203. An oil collecting ring groove 202 is fixedly provided around the upper outer wall of the cyclone separator 2. After centrifugation, the oil can enter the oil collecting ring groove 202 through the overflow notch 203 for preliminary separation and collection. A second liquid level gauge 204 is installed on the wall of the cyclone separator 2 between the oil collecting ring groove 202 and the side-cut inlet pipe 201, which is convenient for controlling the water discharge to fill most of the space of the cyclone separator 2 in advance. The bottom of the oil collecting ring groove 202 is connected to the sewage treatment plant 4 together with the first oil drain pipe 15 through the second oil drain pipe 10. As needed, the first oil drain pipe 15 and the second oil drain pipe 10 are both equipped with an oil drain valve and an oil pump, which can control the oil discharge amount and provide oil discharge power when needed; The oil storage tank 1 includes an external floating roof 101 that can float up and down along the tank wall. A baffle ring 102 is coaxially fixed to the upper cover surface of the external floating roof 101 to divide the baffle ring 102 into a rain collecting trough and a mixing ring trough inside and outside. The rain collecting trough and the mixing ring trough can collect most of the clean rainwater that does not contact the tank wall in the middle and a small part of the mixed oil and water that contacts the tank wall, respectively, thereby reducing the processing volume; the bottom of the mixing ring trough is connected to the side cut inlet pipe 201 through a first hose 5; when the transmission power is insufficient, a water pump can be installed on the first hose 5 as needed; the bottom of the rain collecting trough is distributedly connected to a first branch pipe 7 whose end corresponds to the upper port of the cyclone separator 2, a second branch pipe 8 whose end corresponds to the notch of the floating separation tank 301, and a third branch pipe 9 for emptying at the end through a second hose 6, and the pipe bodies of the first branch pipe 7, the second branch pipe 8, the third branch pipe 9, the first hose 5 and the discharge pipe 11 are all equipped with control valves.

[0015] In the external floating roof oil tank sewage separation system of the present invention, when the tank wall of the oil storage tank 1 is exposed and it rains, the control valves on the first hose 5, the third branch pipe 9 and the discharge pipe 11 are first controlled to be closed, and the control valves on the first branch pipe 7 and the second branch pipe 8 are opened, and the clean rainwater collected by the rain collecting trough is put into the cyclone separator 2 and the gravity separation tank 3, and the water level reaches the detection level of the second liquid level gauge 204 and the first liquid level gauge 304, and then feedback control is performed to close the control valves on the first branch pipe 7 and the second branch pipe 8, and the control valves on the first hose 5, the third branch pipe 9 and the discharge pipe 11 are opened. The control valve on the pipe 11 allows the oil and water in the mixed ring groove to enter the cyclone separator 2 first. After centrifugal separation, most of the oil overflows from the overflow gap 203 into the oil collecting ring groove 202, and then is discharged into the sewage treatment plant 4 through the second oil discharge pipe 10. A small amount of oil and rainwater slowly enter the flotation tank 301 through the discharge pipe 11, and then gravity stratification is performed. After stratification, the lower layer of rainwater enters the overflow tank 302 through the overflow gate 303 and is discharged through the first drain pipe 17. After stratification, the upper layer of oil is discharged from the first oil discharge pipe 15 into the sewage treatment plant 4. Embodiment 2:

[0016] When the rainfall is heavy, the gravity separation tank 3 performs continuous flow stratification. In order to enhance the stratification effect, on the basis of the first embodiment, an air intake ring pipe 16 is arranged at the center of the bottom of the floating tank 301. The pipe body of the air intake ring pipe 16 is evenly surrounded by a plurality of upward air intake branches. The air intake ring pipe 16 is connected to the air intake main pipe 14. A one-way valve for one-way air intake is installed on the air intake main pipe 14 to prevent backflow. The outer end of the air intake main pipe 14 is sealed to pass through the floating tank 301 and is connected to the air intake pump 13. Micro bubbles are injected into the floating tank 301 through the air intake pump 13 and the air intake ring pipe 16. These bubbles adhere to the surface of the oil droplets. The buoyancy of the oil droplets is increased, thereby pushing the oil droplets to float to the water surface for easy separation; as needed, a slow-flow water wheel 12 is provided in the discharge pipe 11, and the fluid in the discharge pipe 11 can be used to push the slow-flow water wheel 12 to rotate to slow down the flow rate, so that the fluid can enter the gravity separation tank 3 at a low speed to facilitate stratification. At the same time, the air intake pump 13 can be set as a hand-cranked air intake pump, and the wheel axle of the slow-flow water wheel 12 rotates through the wall of the discharge pipe 11 and is correspondingly connected to the shaking shaft of the air intake pump 13. The rotation energy of the slow-flow water wheel 12 is used to inflate the hand-cranked air intake pump, thereby reducing energy consumption and reducing control costs.

[0017] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the above-mentioned embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the content of the claims involved.

Claims

1. An external floating roof oil tank sewage oil-water separation system, characterized by: The invention comprises an oil storage tank (1), a cyclone separator (2), a gravity separation tank (3) and a downstream sewage treatment plant (4) for collecting and treating oil pollution; the gravity separation tank (3) is divided into a floating tank (301) and an overflow tank (302) by a partition wall, an overflow gate (303) is provided at the lower part of the partition wall, and the floating tank (301) and the overflow tank (302) are respectively provided with a first oil discharge pipe (15) and a first water discharge pipe (17) at the upper end of the tank wall away from the overflow gate (303). A first liquid level gauge (304) is installed on the wall of the floating tank (301) between the oil discharge pipe (15) and the overflow gate (303); the lower port of the cyclone separator (2) is connected to a discharge pipe (11) whose end extends into the floating tank (301); an overflow notch (203) is provided on the side wall of the upper port of the cyclone separator (2) away from the side cut-in pipe (201); an oil collecting ring groove (202) is fixedly provided around the upper outer wall of the cyclone separator (2); the oil collecting ring groove (202) is connected to the side cut-in pipe (201) and the oil collecting ring groove (202) is fixedly provided to the side cut-in pipe (201). A second liquid level gauge (204) is installed on the wall of the cyclone separator (2) between the cut-in pipes (201); the bottom of the oil collecting ring groove (202) is connected to the sewage treatment plant (4) through the second oil discharge pipe (10) and the first oil discharge pipe (15); the oil storage tank (1) comprises an external floating roof (101) capable of floating up and down along the tank wall; a baffle ring (102) is coaxially fixed to the upper cover surface of the external floating roof (101) to divide the baffle ring (102) into a rain collecting groove and a mixing ring groove inside and outside; The bottom of the mixing annular groove is connected to the side-cut inlet pipe (201) through a first hose (5); the bottom of the rainwater collecting groove is connected to a first branch pipe (7) whose end corresponds to the upper port of the cyclone separator (2), a second branch pipe (8) whose end corresponds to the notch of the floating separation groove (301), and a third branch pipe (9) for emptying the end through a second hose (6); and the pipe bodies of the first branch pipe (7), the second branch pipe (8), the third branch pipe (9), the first hose (5) and the discharge pipe (11) are all equipped with control valves.

2. The external floating roof oil tank sewage oil-water separation system according to claim 1 is characterized by: An air intake annular pipe (16) is provided at the center of the bottom of the floating distribution tank (301), and a plurality of upward air intake branch pipes are evenly arranged around the tube body of the air intake annular pipe (16). The air intake annular pipe (16) is connected to an air intake main pipe (14), and a one-way valve for one-way air intake is installed on the air intake main pipe (14). The outer end of the air intake main pipe (14) passes through the floating distribution tank (301) in a sealed manner and is connected to an air intake pump (13).

3. The external floating roof oil tank sewage oil-water separation system according to claim 2 is characterized by: A slow-flow water wheel (12) is provided in the discharge pipe (11); the air intake pump (13) is a hand-cranked air intake pump; the axle of the slow-flow water wheel (12) rotates through the wall of the discharge pipe (11) and is correspondingly connected to the rocking shaft of the air intake pump (13).

4. The external floating roof oil tank sewage oil-water separation system according to claim 1 is characterized by: The oil storage tank (1), the cyclone separator (2) and the gravity separation tank (3) are arranged in sequence from high to low, and a water pump is installed on the first hose (5).

5. The external floating roof oil tank sewage oil-water separation system according to claim 1 is characterized by: An oil discharge valve and an oil pump are installed on both the first oil discharge pipe (15) and the second oil discharge pipe (10).

6. The external floating roof oil tank sewage oil-water separation system according to claim 1 is characterized by: The bottoms of the flotation tank (301) and the overflow tank (302) are both provided with sewage pipes with sewage valves.

Images